Mobile-type electronic apparatus and method for controlling the same

ABSTRACT

A mobile-type electronic apparatus is arranged to input an image picked up by a camera to a display circuit through an image pickup circuit and a communication circuit and to display the image on an LCD panel in a state of being enlarged by an enlargement display optical system. In the mobile-type electronic apparatus, a control circuit is arranged to switch the power supply for the display circuit from one state over to another, according to an operation performed on a switch portion, in such a way as to supply electric power only when the use of the LCD panel and a back light is necessary.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to an electronic apparatus which ismovable easily and quickly, and, more particularly, to a mobile-typeelectronic apparatus arranged to receive image signals and to displayimages, and to a control method for controlling the mobile-typeelectronic apparatus.

[0003] 2. Description of Related Art

[0004] As a result of the recent increase in communication speed, avideo conference system is being developed for practical applications.Meanwhile, a mobile-type electronic apparatus, such as a notebook-typepersonal computer, is being arranged to use a video camera as anaccessory thereof.

[0005] It is important for such a mobile-type electronic apparatus toarrange a small display to be viewable at a large angle of view with ahigh picture quality. One of proposals for attaining this purpose hasbeen disclosed in Japanese Laid-Open Patent Application No. Hei10-191288.

[0006] The art disclosed in Japanese Laid-Open Patent Application No.Hei 10-191288 is the arrangement for displaying a virtual image byenlarging a small liquid crystal panel to a predetermined angle of view.In viewing a picture plane of VGA (640×480 dots) on adirect-viewing-type liquid crystal panel, for example, since theresolution of the eye of man is one minute of angle, in order to enablea viewer who is a little presbyopic to see at a distance of 30 cm, theliquid crystal panel must be of a size diagonally measuring “2×{fraction(5/4)}×30×tan({fraction (1/60)}×640)” cm, i.e., 14.1 cm, with the aspectratio of the picture plane assumed to be 4:3. According to the artdisclosed in Japanese Laid-Open Patent Application No. Hei 10-191288, onthe other hand, an image of high picture quality can be displayed bymeans of a compact display by enlarging a small liquid crystal paneldiagonally measuring 0.5 inch (1.27 cm) to a horizontal angle of view of21.3 degrees.

[0007] Mobile-type electronic apparatuses, such as notebook-typepersonal computers, are arranged in general to use a rechargeablebattery as a power source. However, in order to enhance the portabilityof the apparatus, the body of the apparatus must be reduced in weightand, therefore, must be arranged to save electric energy for use of abattery of small capacity over a long period of time.

[0008] An electronic apparatus disclosed, for example, in JapaneseLaid-Open Patent Application No. Hei 9-322137 is arranged for thispurpose. The electronic apparatus disclosed in Japanese Laid-Open PatentApplication No. Hei 9-322137 is arranged to suppress electric energyconsumption by cutting off a power supply for an image pickup systemincluding a CCD of a TV (video) camera when the electronic apparatus isnot used.

[0009] However, in a mobile-type electronic apparatus as mentionedabove, an image display function is important as well as an image signaltransmitting function. In view of these functions, it is desired to havethe apparatus arranged to be small in size, to be light in weight, to bemovable easily and quickly and to be usable over a long period time withthe battery charged once.

[0010] The electronic apparatus disclosed in Japanese Laid-Open PatentApplication No. Hei 10-191288 is capable of displaying a high qualityimage at a large angle of view and also lessening electric energyconsumption for illuminating the liquid crystal panel, as compared witha direct-viewing-type liquid crystal panel of a relatively large size.The electronic apparatus, however, has a problem in the following point.If the liquid crystal display panel is arranged to use many pixels suchas 180 thousand or 270 thousand pixels or pixels of SVGA for obtaining ahigh picture quality, a number of times of arithmetic operation to beperformed by a control circuit according to image signals coming fromsuch many pixels increases. As a result, electric energy consumptionalso increases.

[0011] The electronic apparatus disclosed in Japanese Laid-Open PatentApplication No. Hei 9-322137 is arranged to save electric energy on theside of the TV (video) camera to be used in photo-taking. However, theelectronic apparatus is not arranged to suppress electric energyconsumption for display. The electronic apparatus thus has a problem inrespect of the electric energy consumption on the side of display.

[0012] In the case of a mobile-type electronic apparatus, such as anotebook-type personal computer, the use of the electronic apparatus forphoto-taking (picking up images) is a special function, as compared withthe use of the electronic apparatus for ordinary information display anddata processing. The length of time of use of the electronic apparatusfor the photo-taking function is expected to be shorter than the use ofthe electronic apparatus for other functions. The electronic apparatusthus has a problem with respect to the arrangement for increasing itsserviceable time obtainable by charging the battery once.

BRIEF SUMMARY OF THE INVENTION

[0013] The invention is directed to the solution of the above-statedproblems. It is, therefore, an object of the invention to provide amobile-type electronic apparatus arranged to lessen electric energyconsumption and to increase the length of serviceable time obtainable bycharging a battery once, and also to provide a method for controllingthe mobile-type electronic apparatus.

[0014] To attain the above object, in accordance with an aspect of theinvention, there is provided a mobile-type electronic apparatus,comprising communication means capable of transmitting and receivingimage data, a display element arranged to display image data,enlargement display means arranged to optically enlarge an image on thedisplay element and to display the enlarged image as a virtual image, adisplay circuit arranged to cause the display element to display imagedata, operation means for controlling the display circuit, and controlmeans for controlling a power supply for the display circuit inaccordance with an operation on the operation means.

[0015] In accordance with another aspect of the invention, there isprovided a mobile-type electronic apparatus, comprising communicationmeans capable of transmitting and receiving image data, a displayelement arranged to display image data, enlargement display meansarranged to optically enlarge an image on the display element and todisplay the enlarged image as a virtual image, a display circuitarranged to cause the display element to display image data, detectingmeans for detecting that a body of the electronic apparatus has beengrasped by hand, and control means for turning on a power supply for apart of or the whole of the display circuit when the detecting means hasdetected that the body of the electronic apparatus has been grasped byhand.

[0016] In accordance with a further aspect of the invention, there isprovided a mobile-type electronic apparatus, comprising communicationmeans capable of transmitting and receiving image data, a displayelement arranged to display information necessary for a communicatingoperation, enlargement display means arranged to optically enlarge animage on the display element and to display the enlarged image as avirtual image, a display circuit arranged to cause the display elementto display image data, discriminating means for discriminating acommunicating state of the communication means, and control means forcontrolling a power supply for the display circuit in accordance with anoutput of the discriminating means.

[0017] In accordance with a still further aspect of the invention, thereis provided a mobile-type electronic apparatus, comprising communicationmeans capable of transmitting and receiving image data, a displayelement arranged to display image data or information necessary for acommunicating operation, enlargement display means arranged to opticallyenlarge an image on the display element and to display the enlargedimage as a virtual image, a display circuit arranged to cause thedisplay element to display image data, detecting means for detectingthat the enlargement display means has been peeped at, and control meansfor controlling a power supply for the display circuit in accordancewith an output of the detecting means.

[0018] The above and further objects and features of the invention willbecome apparent from the following detailed description of preferredembodiments thereof taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0019]FIG. 1 is a block diagram showing the arrangement of a mobile-typeelectronic apparatus according to a first embodiment of the invention.

[0020]FIG. 2 is a block diagram showing the arrangement of a mobile-typeelectronic apparatus according to a second embodiment of the invention.

[0021]FIG. 3 is a perspective view showing the appearance of themobile-type electronic apparatus according to the second embodiment.

[0022]FIG. 4 is a block diagram showing the arrangement of a mobile-typeelectronic apparatus according to a third embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0023] Hereinafter, preferred embodiments of the invention will bedescribed in detail with reference to the drawings.

[0024] (First Embodiment)

[0025] A mobile-type electronic apparatus according to a firstembodiment of the invention is described with reference to FIG. 1.

[0026]FIG. 1 is a block diagram showing the arrangement of essentialparts of the mobile-type electronic apparatus according to the firstembodiment. Referring to FIG. 1, the mobile-type electronic apparatusincludes a communication circuit 1 (communication means), a displaycircuit 2, a control circuit 3 (control means), an LCD (liquid crystal)panel 4 (display element), a back light 5, an enlargement display means6 which is composed of a prism or the like to optically enlarge an imagedisplayed on the LCD panel 4 and to display the enlarged image, a switchmeans 7, an image pickup circuit 8, and a camera using an image sensor,such as a CCD or the like.

[0027] The communication circuit 1 is arranged to be capable oftransmitting and receiving image data as well as data signals of variedkinds to be processed by the electronic apparatus. The communicationcircuit 1 is arranged to be connected to a communication channel. Withthe communication circuit 1 connected to the communication channel, thecommunication circuit 1 can transmit images picked up by the camera 9and audio data etc., taken in through a microphone (not shown) and alsocan receive image data, audio data, etc.

[0028] The communication circuit 1 is provided with a first inputterminal group 1 b, a second input terminal group (not shown), a firstoutput terminal group 1 a and a second output terminal group (notshown).

[0029] The first input terminal group 1 b of the communication circuit 1is connected to an output terminal group 8 c of the image pickup circuit8. The second input terminal group of the communication circuit 1 isconnected to the microphone (not shown). Further, the first outputterminal group 1 a of the communication circuit 1 is connected to afirst input terminal group 2 a of the display circuit 2. The secondoutput terminal group of the communication circuit 1 is connected to aspeaker (not shown). The communication circuit 1 is further connected toa key switch of an operation part (not shown) and is thus arranged to beoperable by a key input operation.

[0030] The display circuit 2 performs a decoding function and alsofunctions as a timing generator in a known manner. An image or characterinformation obtained through the image signal received by thecommunication circuit 1 is caused by the display circuit 2 to bedisplayed on the LCD panel 4, which is a display element.

[0031] The first input terminal group 2 a of the display circuit 2 isconnected to the first output terminal group la of the communicationcircuit 1 to receive image signals from the communication circuit 1. Afirst output terminal group 2 c and a second output terminal group 2 dof the display circuit 2 are connected respectively to the LCD panel 4and the back light 5.

[0032] The display circuit 2 forms a signal conforming to the pixelarray of the LCD panel 4 on the basis of a signal input from thecommunication circuit 1 to the first input terminal group 2 a and sendsthe formed signal to the LCD panel 4 to form an image on the LCD panel4. The display circuit 2 also causes the back light 5 to light up.

[0033] The second input terminal group 2 b is provided on the displaycircuit 2 for control over the power supply for the display circuit 2,the LCD panel 4 and the back light 5. The power supply for the displaycircuit 2, the LCD panel 4 and the back light 5 is turned on, forexample, when the second input terminal group 2 b is at a predeterminedvoltage, i.e., at a high (H) level, and the power supply for the displaycircuit 2, the LCD panel 4 and the back light 5 is turned off when thesecond input terminal group 2 b is at another predetermined voltage,i.e., at a low (L) level.

[0034] The LCD panel 4 is a display panel using, for example, a knownTFT liquid crystal element and is connected to the first output terminalgroup 2 c of the display circuit 2. The LCD panel 4 is thus arranged toform an image based on a signal received from the display circuit 2.

[0035] The back light 5 is a surface-light-emitting light source, whichis composed of, for example, an LED and a light guiding plate. The inputterminal group of the back light 5 is connected to the second outputterminal group 2 d of the display circuit 2. The back light 5 is thusarranged to light up in accordance with the state of the second outputterminal group 2 d of the display circuit 2.

[0036] The enlargement display means 6 is in the form of a free curvedprism obtained, for example, by molding a transparent plastic material.The enlargement display means 6 and the LCD panel 4 are fixed at theirrelative positions where the image on the LCD panel 4 has apredetermined diopter and where the angle of view shows each pixel ofthe LCD panel 4 at least at an angle of about one minute. The image onthe LCD panel 4 is thus displayed in an enlarged state as a virtualimage. A prism optical system disclosed in Japanese Laid-Open PatentApplication No. Hei 7-333551, for example, may be employed as the freecurved prism.

[0037] The switch means 7 represents an operation means. The switchmeans 7, which is, for example, of a push type, has a terminal groupthereof connected to a first input terminal group 3 a of the controlcircuit 3.

[0038] The control circuit 3 is provided with the first input terminalgroup 3 a and first and second output terminal groups 3 b and 3 c. Thefirst and second output terminal groups 3 b and 3 c are arranged to bein their predetermined states according to the state of the first inputterminal group 3 a.

[0039] For example, the control circuit 3 is arranged to set the firstand second output terminal groups 3 b and 3 c at low (L) level stateswhen the first input terminal group 3 a is in an open state, and to setthe first and second output terminal groups 3 b and 3 c at high (H)level states when the first input terminal group 3 a is in a closedstate.

[0040] The first output terminal group 3 b of the control circuit 3 isconnected to the second input terminal group 2 b of the display circuit2. The control circuit 3 is thus arranged to change the state of thepower supply for the display circuit 2, the LCD panel 4 and the backlight 5 from one state over to another according to the state of theswitch means 7.

[0041] More specifically, the state of the first output terminal group 3b of the control circuit 3 takes the high (H) level state when the inputterminal group 3 a is in the closed state with the switch means 7operated. The high level state of the first output terminal group 3 b ofthe control circuit 3 causes the display circuit 2 to form an image onthe LCD panel 4 according to an input signal coming from the first inputterminal group 2 a and also to light up the back light 5.

[0042] When the first input terminal group 3 a of the control circuit 3is in the open state with the switch means 7 not operated, the firstoutput terminal group 3 b of the control circuit 3 takes the low (L)level state to cause the display circuit 2 to turn off its power supplyand the power supply for the LCD panel 4 and also to put out the backlight 5.

[0043] The image pickup circuit 8 is arranged to compose and encodeimage signals obtained by the camera 9 into transmissible signals. Thecamera 9 is a known CCD camera. The image pickup circuit 8 is providedwith first and second input terminal groups 8 a and 8 b and a firstoutput terminal group 8 c.

[0044] The second input terminal group 8 b of the image pickup circuit 8is connected to the output terminal group of the camera 9. The firstoutput terminal group 8 c of the image pickup circuit 8 is connected tothe first input terminal group 1 b of the communication circuit 1. Withan image signal obtained by the camera 9 inputted to the image pickupcircuit 8, the image pickup circuit 8 converts the image signal into atransmissible signal and sends the transmissible signal out to thecommunication circuit 1. The first input terminal group 8 a of the imagepickup circuit 8 is provided for control over the power supply for theimage pickup circuit 8 and the camera 9. For example, the power supplyfor the image pickup circuit 8 and the camera 9 is turned on when thefirst input terminal group 8 a of the image pickup circuit 8 is at apredetermined voltage, i.e., at a high (H) level, and the power supplyfor the image pickup circuit 8 and the camera 9 is turned off when thefirst input terminal group 8 a of the image pickup circuit 8 is at avoltage of 0V, i.e., at a low level.

[0045] The first input terminal group 8 a of the image pickup circuit 8is connected to the second output terminal group 3 c of the controlcircuit 3. Therefore, when the input terminal group 3 a of the controlcircuit 3 is in the closed state with the switch means 7 operated, thelevel of the second output terminal group 3 c of the control circuit 3becomes high (H) to cause the image pickup circuit 8 to turn on thepower supply for the camera 9. Then, an image signal obtained by thecamera 9 is inputted to the image pickup circuit 8 to be sent out to thecommunication circuit 1 in the form of a transmissible signal. Further,when the input terminal group 3 a is in the open state with the switchmeans 7 not operated, the level of the second output terminal group 3 cof the control circuit 3 becomes low (L) to cause the image pickupcircuit 8 to turn off its power supply and also the power supply for thecamera 9.

[0046] As described above, the mobile-type electronic apparatusaccording to the first embodiment of the invention is arranged toconsume the electric energy of the power supply for the image displaysystem only when the switch means 7 is operated by the user of theapparatus. While the apparatus is in a normal state, the power supplyfor a part of or whole of the display circuit 2 is kept in an off-state,so that electric energy can be much saved while the apparatus is usedfor normal talking by voices only or while the apparatus is in a standbystate.

[0047] The switch means 7 is arranged to be a push-type switch. The useof the push-type switch has an advantage in that the push-type switchclearly reflects what is intended by the user in respect of the imagedisplay operation and the image pickup operation, so that electricenergy can be effectively saved. However, the use of the push-typeswitch is not always advantageous in terms of operability.

[0048] In a case where importance is set on operability, the known touchsensor of a pressure sensitive type or a capacity detecting type may beused as the switch means 7. In such a case, a known detecting circuitwhich corresponds to the above touch sensor is arranged within thecontrol circuit 3. Such an arrangement relieves the user from thetroublesomeness of a switch operation and also saves electric energyduring a standby period.

[0049] In the case of the first embodiment, the power supply for theimage pickup system is arranged to be cut off also by operating theswitch means 7. However, the arrangement may be changed to arrange theimage pickup system separately from the display system. Such amodification effectively saves consumption of the electric energy by theimage pickup system in a case, for example, where the mobile-typeelectronic apparatus is connected to the Internet to see a home page.

[0050] (Second Embodiment)

[0051] The first embodiment is arranged to detect that the switch means7 provided on the mobile-type electronic apparatus has been operated orthat the mobile-type electronic apparatus has been grasped by the handof the user. However, a second embodiment of the invention is arrangedto detect that the user has peeped at a display part. This arrangementof the second embodiment ensures electric energy saving without anytroublesome operation.

[0052] An example of the arrangement for controlling a power supply fora display system by detecting that the user has peeped at the displaypart is next described below with reference to FIGS. 2 and 3, which showa mobile-type electronic apparatus according to the second embodiment.

[0053] Referring to FIGS. 2 and 3, the mobile-type electronic apparatusis provided with a light projecting element 10, a CCD sensor 11 and animage processing circuit 11. The light projecting element 10, the CCDsensor 11 and the image processing circuit 12 jointly form a detectingmeans for detecting whether or not the user has peeped at a prismoptical system, which is used as the enlargement display means 6. Thisdetecting means plays the role of the switching means 7 mentioned in thefirst embodiment described above.

[0054] As shown in FIG. 3, which is a perspective view of themobile-type electronic apparatus, the light projecting element 10 andthe CCD sensor 11 are disposed at a peep window part of the enlargementdisplay means 6 so as to detect that the user has peeped at the opticalenlargement display means 6, which is composed of a prism or the like.

[0055] The light projecting element 10 is an infrared LED. When the useris peeping at the enlargement display means 6, the eyeball of the useris illuminated by the light projecting element 10. As a result, anintrinsic pattern appears on the CCD sensor 11. Then, the imageprocessing circuit 12 makes a check to find whether or not the image ofthis intrinsic pattern on the CCD sensor 11 is brought forth by theeyeball. If so, the image processing circuit 12 outputs a high (H) levelsignal. If not, the image processing circuit 12 outputs a low (L) levelsignal.

[0056] A control circuit 13 is arranged to form its output signal at ahigh level or a low level according to the state of an input terminalgroup 13 a. However, to prevent a power supply for an image displaysystem from turning on or off every time the user winks, the controlcircuit 13 is provided with a delay circuit which is arranged to make asuitable length of delay of about 100 msec at which no erroneousdetection is made in response to any relatively short disturbance suchas winking of the user.

[0057] This arrangement enables the user to turn on the power supply forthe display system only when the user wishes to view images on display.Therefore, the second embodiment not only gives an adequate operabilityand a good feeling of use but also saves electric energy.

[0058] Further, as shown in FIG. 3, the provision of a display element14 for a display of information on such an operation as making a checkfor a telephone number or the like further enhances the utility and theelectric energy saving effect of the second embodiment.

[0059] (Third Embodiment)

[0060] In the first and second embodiments described above, the powersupply for the display system is controlled according to the state ofuse of the mobile-type electronic apparatus. It is also possible toarrange a mobile-type electronic apparatus to decide whether or not ahigh definition display is necessary according to the current state ofcommunication of the apparatus by detecting the communication state, toturn on the power supply if a high definition display is decided to benecessary and, if not, to turn the power supply off.

[0061] One example of such an arrangement is described below as a thirdembodiment of the invention with reference to FIG. 4. Referring to FIG.4, a control circuit 15 has an input terminal group 15 a connected to acommunication circuit 1 and an output terminal group 15 b connected to adisplay circuit 2. The communication circuit 1 is arranged to output tothe control circuit 15 information on the amount of communication dataper unit time. If the amount of communication data per unit time isfound to be less than a predetermined value and the communication isfound to be continuously conducted, a discriminating means, which isincluded in the control circuit 15, recognizes the communication stateas communication by voices only. If the result of a check made by thediscriminating means indicates that the communication is conducted byvoices only, the control circuit 15 causes the power supply for thedisplay system to turn off for electric energy saving.

[0062] Further, the electric energy saving may be attained bydiscriminating the respective properties of an image signal and an audiosignal and turning off the power supply for the display system if it isfound that the communication for the audio signal only is conducted.

[0063] With a mobile-type electronic apparatus arranged in this manner,the electric energy consumption can be lessened without additionallyarranging any special sensor, any special switch or the like. Accordingto the arrangement of the third embodiment, therefore, the mobile-typeelectronic apparatus can be arranged to be compact in size, to be lightin weight and to be usable over a long period of time with its batterycharged once.

[0064] In each of the first to third embodiments described above, thesupply of electric power to the display system is controlled accordingto the state of use and the state of display of the mobile-typeelectronic apparatus. Therefore, the electric power to be consumed fordisplays is lessened to increase a period of time for which themobile-type electronic apparatus can be rendered usable by charging itsbattery once.

[0065] Further, the arrangement for adaptively controlling the powersupply for the image display circuit either in part or in its entiretyaccording to the state of use of the apparatus by the user not onlyenhances the operability of the apparatus but also effectively minimizesthe amount of electric energy consumed for the required operation.Therefore, according to the arrangement of the invention disclosed, amobile-type electronic apparatus can be arranged to consume a smallamount of electric energy.

1. A mobile-type electronic apparatus, comprising: communication meanscapable of transmitting and receiving image data; a display elementarranged to display image data; enlargement display means arranged tooptically enlarge an image on said display element and to display theenlarged image as a virtual image; a display circuit arranged to causesaid display element to display image data; operation means forcontrolling said display circuit; and control means for controlling apower supply for said display circuit in accordance with an operation onsaid operation means.
 2. A mobile-type electronic apparatus, comprising:communication means capable of transmitting and receiving image data; anoperation information display element arranged to display informationnecessary for performing a communicating operation; an image displayelement arranged to display image data; enlargement display meansarranged to optically enlarge an image on said image display element andto display the enlarged image as a virtual image; a display circuitarranged to cause said image display element to display image data;operation means for controlling said display circuit; and control meansfor controlling a power supply for said display circuit in accordancewith an operation on said operation means.
 3. A mobile-type electronicapparatus according to claim 1 or 2 , wherein said operation means iscomposed of a switch arranged to change an output thereof every timesaid switch is manually operated.
 4. A mobile-type electronic apparatus,comprising: communication means capable of transmitting and receivingimage data; a display element arranged to display image data;enlargement display means arranged to optically enlarge an image on saiddisplay element and to display the enlarged image as a virtual image; adisplay circuit arranged to cause said display element to display imagedata; detecting means for detecting that a body of said electronicapparatus has been grasped by hand; and control means for turning on apower supply for a part of or the whole of said display circuit whensaid detecting means has detected that the body of said electronicapparatus has been grasped by hand.
 5. A mobile-type electronicapparatus, comprising: communication means capable of transmitting andreceiving image data; a display element arranged to display informationnecessary for a communicating operation; enlargement display meansarranged to optically enlarge an image on said display element and todisplay the enlarged image as a virtual image; a display circuitarranged to cause said display element to display image data;discriminating means for discriminating a communicating state of saidcommunication means; and control means for controlling a power supplyfor said display circuit in accordance with an output of saiddiscriminating means.
 6. A mobile-type electronic apparatus according toclaim 5 , wherein said control circuit turns on the power supply forsaid display circuit when said discriminating means has detected a stateof communicating image data or information to be displayed, and turnsoff the power supply for a part of or whole of said display circuit whensaid discriminating means has detected a state of communicating an audiosignal only.
 7. A mobile-type electronic apparatus, comprising:communication means capable of transmitting and receiving image data; adisplay element arranged to display image data or information necessaryfor a communicating operation; enlargement display means arranged tooptically enlarge an image on said display element and to display theenlarged image as a virtual image; a display circuit arranged to causesaid display element to display image data; detecting means fordetecting that said enlargement display means has been peeped at; andcontrol means for controlling a power supply for said display circuit inaccordance with an output of said detecting means.
 8. A mobile-typeelectronic apparatus according to claim 7 , wherein said control circuitturns on the power supply for said display circuit when said detectingmeans has detected that said enlargement display means has been peepedat, and turns off the power supply for a part of or whole of saiddisplay circuit when said detecting means has detected that saidenlargement display means is not peeped at.